I borrowed a Rebco Caster/Camber gauge to do my alignment this last week. It has a magnetic base and is made to attach to a race car hub or brake rotor. Since the magnet will not fit inside the wheels I chose to attach the gauge to the rotors fitting it between the spokes.

There seems to be some variation in camber readings depending where I place the gauge on the rotor. At first I thought the issue was because I had it attached across both the fire path and the part of the rotor that doesn't get worn so I made sure it was attached only in the fire path and if need be hanging off the edge of the rotor. In the rear of the car if I place the gauge behind the tie rod I get a reading of -1.5, if I place the gauge above the spindle I get a reading of -1.25, if I place the gauge below the spindle I get a reading of -1.75. There must be a reason for this but I am not sure what it is. Does the variation in readings indicate the rotor has tapered with the inner portion of the rotor thinner than the outer portion? As for lateral thickness variation I don't have any brake thumping or irregularity.

Right now I am assuming the closest reading is the one behind the spindle since if the rotor has taper it will be oriented vertically in that position and shouldn't affect the gauge reading.

Any idea what is going on? Comments/suggestions would be appreciated.

Bill

 

I don't know why those spots would read differently, but I agree that behind the spindle would cancel out any rotor taper issues.

 

I am going to take a wild guess. It may be because the arc of the A arms is not constant, and given where they are at, when the car is sitting on the suspension. The brake rotor may or may not be square. I'm just throwing out an idea! Dave Farmer could give a better answer. I use his instructions and to do all of my alignment setup with 2 straight edges and a digital Sears level and a tape measure. I have also had variations from one side of a wheel to the other and the center. JD

 

Personally I use the digital smart camber gauge to set alignment.

I would be having second thoughts about that tool, with getting different measures at different attachment points.

I know some good ol guy will now post how he has used it forever & won races with it and so on, but still, the digital ones are very easy & fool proof to use & it takes some time to do a good alignment, be a shame to waste all that time with a bubble gauge that's reading off.



The smart camber come off 3 hard points on each rim, it's not going to introduce error, where a bubble gauge nearer the axle center, may........